Further matured with features like an upside-down front fork 2005 European market new model "YZF-R6" Debuts at 4th INTERMOT Show

Yamaha Motor Co., Ltd. (YMC) displays the new 2005 European market model Yamaha Torque Sports "YZF-R6" at the INTERMOT Munich 2004 (4th International Trade Fair for Motorcycles and Scooters) held over five days beginning from September 15, 2004 (Press days from 13th).

The new YZF-R6 adopts features including (1) an engine with improved performance due to boosted intake efficiency, (2) a frame with optimized rigidity balance, (3) a highly rigid upside-down front fork and (4) a radial mount front brake.
All these improvements represent far more than what is normally considered a “minor change” model revision and contribute to a dramatic boost in performance. The existing model concept of an “exciting best 600cc supersport” has been continued while taking new measures to further refine the outstanding handling on public roads and secondary roads. At the same time, it achieves a big boost in performance on closed courses.

After the original "YZF-R6" made its debut in September 1998 at the 1st Intermot show and was released in the European and North American markets in 1999, it immediately won high acclaim as "a supersport model that lets you fully enjoy the power of a 600cc engine" and set a new standard in the mid-class supersport bike category. It soon gathered great customer support due to its "Fastest and most exciting 600cc model on winding roads" product concept. Later its outstanding performance would be proven on the race track when it became the championship machine in the 2000 World Supersport Championships. Then the YZF-R6 reappeared in 2003 in its first substantial model change in the four years, featuring new designs for roughly 90% of its parts. By achieving further evolution throughout its mechanisms while maintaining the original model concept, the current YZF-R6 also won a strong user following.

However, today’s 600cc supersport class in Europe has seen the entry of many competitive models from the various makers that have stimulated the market, and the call from the marketplace is for models that deliver higher levels of closed-course (circuit) performance. In light of these conditions, the new YZF-R6 has been developed for improved product value by maintaining the original product concept of "Fastest and most exciting 600cc model on winding roads" while adopting new technologies throughout to achieve a further maturation of the basic performance factors in order to boost performance in closed-course riding.

Engine

1) Revised throttle body diameter
The engine retains the same bore x stroke, compression ratio, combustion chamber shape and other specs as the existing model but major changes have been made in the intake system that have improved the power output and torque characteristics. First of all, in order to increase power output and high-end response, the throttle body diameter has been increased from 38 mm to 40 mm. To accommodate this, the fuel pressure level for the fuel injection system's injector has also been increased and the injection map and ignition timing map optimized. The combined effect of these improvements gives excellent combustion characteristics and contributes to outstanding drivability.
While keeping the rpm level of maximum power output at 13,000 rpm, these improvements create a power increase of about three horsepower, making the new spec for max power output 120 PS/13,000 rpm (NA: at natural intake).

2) New intake funnel shape
To accommodate the increased throttle body diameter, the funnel mouth was widened from a diameter of 39.4 to 41.6 mm. The funnel length was also shortened for cylinders 1 and 4 and kept the same for 2 and 3.
These new funnel specs contribute to excellent torque characteristics especially at the time of intake/exhaust valve overlap from the mid-speed range up. This means linear, easy to use torque characteristics across the full rpm range.

3) Twin ring type radiator fans
In order to ensure stable power output from the powered-up engine, the radiator fan has been change from the previous single unit to twin ring type radiator fans. While offering very efficient use of space in the radiator assembly, this new system also provides optimum fit with the increased front wheel size and other chassis specs.


Chassis

1) New Deltabox III frame with revised rigidity balance
While maintaining the exterior appearance and basic structure of the existing frame the new "Deltabox III" frame has been further developed by reviewing all the detail elements from the standpoint of rigidity balance. In particular, the thickness of the aluminum used in the attachment assembly for the bottom side of the rear suspension link was increased in steps to achieve an optimum rigidity balance.

2) Upside-down front fork adopted
In order to achieve excellent handling stability and stability during braking, the new YZF-R6 adopts an upside-down (inverted) front fork with independent adjustment mechanisms for initial load, compression stroke damping and rebound stroke damping and 41 mm inner tubes. Also, to ensure excellent rigidity balance, a mutual optimization of the exterior diameter of the inner tubes, their wall thickness and the exterior diameters of the outer tubes was undertaken.
Furthermore, the addition of a new cast aluminum handlebar crown and forged aluminum under-bracket combines with the high longitudinal rigidity of the frame to produce excellent handling qualities typified by excellent stability when entering a turn.

3) New rear suspension spec
To optimize the match with the dimension changes and new upside-down (inverted) front fork, changes were made in the variance ratio of the link lever and the rigidity of the link and the spring rate.

4) 70 radial front tire
To ensure excellent drivability the front tire size has been changed from the existing 120/60 ZR17 M/C to a 120/70 ZR17 M/C characterized by the large profile area which in turn increases design freedom.

5) New-design front brake
Yamaha developed a new brake system for this model with the aim of achieving outstanding stopping power and controllability. The existing 298mm/t5 front brake disc was replaced by a new-design lightweight 310mm/t4.5mm disc. While the disc rotor has the same exterior appearance as that on the YZF-R1, it has in fact been newly designed for this model to contribute to an optimum gyro moment of the front wheel assembly, which directly affects handling stability. (The YZF-R1 mounts a 320 mm disc)
The brake caliper is a radial mount type that is adopted together with a new-design lightweight, high-rigidity axle bracket. Also, the master cylinder is a radial pump type that is complemented by the adoption of a new brake lever design. With the adoption of these new parts in the three main components of the brake system, Yamaha’s engineers have worked to achieve a high level of braking performance that integrates optimized overall system rigidity, including everything from hose tension to lever ratio, and operational feeling.

6) Other changes
Other spec changes include (1) a new side stand spec and (2) a revised under cowl spec.